Generac Power Systems 53187 - Manual (Page 42)

SECTION 1.7- TROUBLESHOOTING
(UNITS WITH 10 INCH STATOR) 1 PARTI
THE REVOLVING FIELD AC GENERATOR
Diagnostic Tests
INTRODUCTION:
The follow ing ‘Diagnotic Tests" correspond to the
num bered tests In the troubleshooting “Flow Charts" on
Pages 1.7-1 through 1.7-3. W hen perform ing tests, it is
recom m ended that the w iring diagram and/or electrical
schem atic for the appropriate generator m odel be re­
ferred to as often as necessary.
TEST 1- CHECK AC OUTPUT VOLTAGE:
Discussion: This test m ust be perform ed to help
you determ ine if a problem exists and the exact nature
of the problem . Som e installed units w ill include an*
optional m eter package, w hich includes an AC voltm e­
ter. Even if such an optional package is installed, it is a
good idea to check the voltage w ith an external m eter
such as a VOM. Using an external m eter w ill help you
determ ine if the AC voltm eter on the optional m eter
panel is accurate.
Procedure: If the generator is installed in a m otor
hom e, the VOM test probes can be inserted into a
convenient AC outlet that is supplied by the generator.
If uninstalled, connect the VOM test leads across AC
outlet leads T1 (red), T2 (w hite) and T3 (black). See
Figure 1.
NOTE: Rem em ber, the unit m ay be connected for
either singie voltage (120 voits) or duai voitage
(120/240 voits). See "STATOR AC CONNECTiON
SYSTEM " on Page 1.5-2.
Start the generator engine, let it stabilize and w arm
up. Read the line-to-line or line-to-neutral voltage from
the VOM. Reading should be as follow s:
Line T1 (red) to T2 (w hite) = 121-127 volts
Line T3 (black) to T2 (w hite) = 121-127 volts
Line T1 (red) to T3 (black) = 242-254 volts
fWiRm rtrwtRPi
) CB1
44
k
CB2 )
-120V.
T2
(WHFTE)
------------ ► <«-------- 120V.
T1
(RED)
■ 240V. ■
T3
SHOWN CONNECTED FOR DUAL (BLACK)
VOLTAGE AC OUTPUT. FOR 120
VOLTS OUTPUT, SEE FIGURE S
ON PAGE 1.5-2.
Results;
1. If zero or residual voltage at no-load is indicated, go
to Problem 1 of the "Flow Charts".
2. If the no-load voltage Is low , but is greater than
residual voltage, go to Problem 2 of the "Flow Charts'.
3. If no-load voltage is high, go to Problem 3 of the "Flow
Charts".
TEST 2- CHECK MAIN CIRCUIT BREAKERS:
Discussion: The generator is equipped w ith tw o
m ain circuit breakers, designated CB1 and CB2, as
standard equipm ent. If these circuit breakers are set
to their "Off" or "Open" position, or if they have failed
open, generator AC ou^ut voltage to the load(s) w ill
not be available.
Procedure: Check the m ain circuit breakers, m ake
sure they are set to "On" or "Closed". If the breakers
are set to "On* or "Closed", but AC output voltage is not
available, use a VOM to test the breakers as follow s:
1. Shut the engine dow n.
2. Inspect the AC w iring connections carefully. Make
sure w iring is properly connected for the correct volt­
age. See "STATOR AC CONNECTION SYSTEM" on
Page 1.5-2.
3. Set the VOM to its "Rxl" scale and zero the m eter.
Then, test the breakers as follow s:
a. Connect the VOM test probes across circuit
breaker CB1 term inals. W hen breaker is set to its'"^ ,
"On" or "Closed" position, the VOM should read
"continuity". W hen set to "Off" or "Open" position,
“infinity" should be read.
b. Repeat the above test for circuit breaker CB2.
Results should be the sam e.
Results:
1. If circuit breakers are good, go to Test 3.
2. Replace any defective circuit breaker(s).
Figure 1. Stator AC Output V oltage Figure 2. M ain Circuit Breaker Test Points
PAGE 1.7-4